CN106556996B - image forming device - Google Patents

Abstract

The invention provides an intermediate transfer unit and an image forming device. The intermediate transfer unit of the present invention has an intermediate transfer belt, a plurality of transfer rollers, a pair of side walls, and a plurality of legs. When the intermediate transfer unit is detached from the apparatus main body, the plurality of leg portions abuts on a predetermined installation surface. At least three legs are arranged on the lower end portions of the pair of side walls. At least one of the pair of side walls includes a shaft protruding in the first direction. At least one of the plurality of legs is rotatable around the shaft, and is rotatable between a first posture capable of supporting the intermediate transfer unit detached from the device main body and a second posture that can rotate around the shaft from the first posture. Movable legs for pose changes. According to the present invention, the maintainability of the intermediate transfer unit is improved.

Description

image forming device

technical field

The present invention relates to an intermediate transfer unit and an image forming apparatus including the intermediate transfer unit.

Background technique

An image forming apparatus including a photosensitive drum and an intermediate transfer unit is known as a typical image forming apparatus such as an electrophotographic printer or copier. The photosensitive drum carries an electrostatic latent image. An intermediate transfer unit transfers a toner image from the photosensitive drum onto a sheet. In order to transfer an image composed of a plurality of colors representing a full-color image onto a sheet, the intermediate transfer unit includes an intermediate transfer belt and a primary transfer roller. The intermediate transfer belt rotates facing the plurality of photosensitive drums, and the toner is transferred from each photosensitive drum to the intermediate transfer belt by a primary transfer voltage applied to the primary transfer roller.

A technique has been proposed in which an intermediate transfer unit and a drum unit supporting a photosensitive drum are respectively detachable from the main body of the image forming apparatus. In addition, an interference preventing member that prevents interference between the intermediate transfer belt and the drum unit at the time of attachment and detachment has also been proposed.

When the intermediate transfer belt is detachable from the apparatus main body, the intermediate transfer belt is easily damaged when the intermediate transfer unit is placed on the ground. On the other hand, there is a problem that the damage prevention member for preventing such damage easily interferes with other units inside the device main body.

Contents of the invention

An intermediate transfer unit according to one aspect of the present invention is relative to a device including a plurality of photosensitive drums that rotate around an axis extending in a first direction and are adjacently arranged at intervals along a second direction intersecting the first direction. The main body is attached along the second direction so as to be adjacent to the plurality of photosensitive drums. The intermediate transfer unit has an intermediate transfer belt, a plurality of transfer rollers, a pair of side walls, and a plurality of legs. The intermediate transfer belt is rotationally driven in the second direction, and carries on its surface the toner images transferred from the plurality of photosensitive drums. The plurality of transfer rollers are disposed opposite to the photosensitive drums with the intermediate transfer belt interposed therebetween. The pair of side walls are arranged on both end sides in the first direction to extend in the second direction and rotatably support the intermediate transfer belt. When the transfer unit is detached from the apparatus main body, the plurality of leg portions abuts on a predetermined installation surface. At least three of the leg portions are arranged on the lower end portions of the pair of side walls. At least one of the pair of side walls includes a shaft protruding in the first direction. At least one of the plurality of leg portions is rotatable around the shaft portion, and is in a first posture capable of supporting the intermediate transfer belt detached from the apparatus main body and rotates from the first posture. A movable leg capable of changing the posture between the second postures in which the shaft rotates.

It is possible to prevent the intermediate transfer belt from being damaged when it is placed on the floor, and to prevent interference with other units in the main body of the device.

Description of drawings

FIG. 1 shows a cross-section of an internal structure of an image forming apparatus according to an embodiment of the present invention.

FIG. 2A shows an oblique view of the intermediate transfer unit according to the first embodiment.

FIG. 2B shows an oblique view of the intermediate transfer unit according to the first embodiment.

FIG. 3A shows an enlarged oblique view of a part of the intermediate transfer unit according to the first embodiment.

FIG. 3B shows an enlarged oblique view of a part of the intermediate transfer unit according to the first embodiment.

FIG. 4 shows an enlarged oblique view of a part of the intermediate transfer unit according to the first embodiment.

FIG. 5 is an exploded perspective view showing a part of the intermediate transfer unit according to the first embodiment.

FIG. 6 obliquely shows a state in which a movable leg is removed from a part of the intermediate transfer unit according to the first embodiment.

FIG. 7 obliquely shows a state in which a movable leg is attached to a part of the intermediate transfer belt according to the first embodiment.

FIG. 8 shows an enlarged oblique view of a part of the movable leg according to the first embodiment.

Fig. 9 shows the movable leg according to the first embodiment from the front.

FIG. 10 shows a cross section of the movable leg according to the first embodiment.

FIG. 11 shows the periphery of the movable leg portion of the intermediate transfer unit according to the second embodiment of the present invention from the front.

Fig. 12 is an enlarged front view showing a part of the movable leg according to the second embodiment.

FIG. 13 shows obliquely the periphery of the movable leg portion of the intermediate transfer unit according to the third embodiment of the present invention.

FIG. 14 shows a slanted view of the movable leg and the detection unit of the intermediate transfer unit according to the third embodiment.

FIG. 15 shows enlarged and oblique views of the movable leg and the detection unit according to the third embodiment.

FIG. 16 shows obliquely the periphery of the movable leg portion of the intermediate transfer unit according to the fourth embodiment of the present invention.

FIG. 17 obliquely shows a state where the movable leg is detached from the intermediate transfer unit according to the fourth embodiment.

Detailed ways

Next, the image forming apparatus 10 according to the embodiment of the present invention will be described in detail based on the drawings. In this embodiment, a tandem color printer will be described as an example of an image forming apparatus. The image forming apparatus may be, for example, a copier, a facsimile apparatus, a multifunction machine thereof, or the like.

FIG. 1 shows a cross-section of an internal structure of an image forming apparatus 10 . The image forming apparatus 10 includes an apparatus main body 11 having a box-shaped housing structure. A paper feeding unit 12 , an image forming unit 13 , an intermediate transfer unit 14 , a secondary transfer roller 145 , a toner supply unit 15 , and a fixing unit 16 are built in the apparatus main body 11 . The sheet feeding section 12 conveys the sheet P. The image forming section 13 forms a toner image to be transferred onto the sheet P fed by the paper feeding section 12 . The intermediate transfer belt 14 primarily transfers the toner images. The toner supply unit 15 supplies toner to the image forming unit 13 . The fixing section 16 performs a process of fixing the unfixed toner image formed on the sheet P on the sheet P. As shown in FIG. In addition, a paper discharge unit 17 is provided on an upper portion of the apparatus main body 11 . The sheet P subjected to the fixing process by the fixing unit 16 is discharged to the paper discharge unit 17 .

In the apparatus main body 11 , a sheet transport path 111 extending in the vertical direction is formed on the right side of the image forming unit 13 . A pair of conveyance rollers 112 and a pair of registration rollers 113 for conveying a sheet to an appropriate position are provided on the sheet conveyance path 111 . The sheet transport path 111 is a transport path for transporting the sheet P from the paper feeding unit 12 to the paper discharge unit 17 via the image forming unit 13 (secondary transfer nip unit) and the fixing unit 16 .

The paper feeding unit 12 includes a paper feeding tray 121 , a pickup roller 122 , a pair of paper feeding rollers 123 , and a manual tray 124 . The paper feed tray 121 stores a bundle of sheets P1 in which a plurality of sheets P are laminated.

In addition, the image forming apparatus 10 includes a right cover unit 10R (see FIG. 1 ). The right cover unit 10R defines the side of the right side of the device main body 11 . The right cover unit 10R includes a cover fulcrum portion 10R1. The right cover unit 10R can be opened in the direction of arrow DA with respect to the device main body 11 around the cover fulcrum portion 10R1 . The secondary transfer roller 145 , the right roller of the registration roller pair 113 , and the like are rotatably supported on the right cover unit 10R. Also, when the right cover unit 10R is opened, the sheet transport path 111 is exposed to the outside of the apparatus main body 11 . In this state, the intermediate transfer unit 14 can be mounted inside the apparatus main body 11 .

The image forming section 13 forms a toner image to be transferred onto the sheet P, and is provided with a plurality of image forming units for forming toner images of different colors. As the image forming unit, in this embodiment, there are provided magenta (M ) developer for magenta 13M, cyan unit 13C using cyan (C) developer, yellow unit 13Y using yellow (Y) developer, and black unit 13BK using black (Bk) developer. Each unit 13M, 13C, 13Y, and 13BK includes a photosensitive drum 20 (image carrier), a charging device 21 arranged around the photosensitive drum 20 , a developing device 23 , and a cleaning device 25 . Moreover, the exposure device 22 common to each unit 13M, 13C, 13Y, and 13BK is arranged below the image forming unit.

The photosensitive drum 20 is driven to rotate around its axis, and an electrostatic latent image and a toner image are formed therearound. In addition, the rotation axis of the photosensitive drum 20 extends in the front-rear direction (first direction, a direction perpendicular to the paper surface of FIG. 1 ). As the photosensitive drum 20, a photosensitive drum using an amorphous silicon (a-Si)-based material can be used. In addition, as shown in FIG. 1 , a plurality of photosensitive drums 20 corresponding to respective colors are arranged at intervals in a second direction (left-right direction or horizontal direction) intersecting the first direction.

The charging device 21 uniformly charges the surface of the photosensitive drum 20 . The exposure device 22 forms an electrostatic latent image by irradiating the uniformly charged peripheral surface of the photosensitive drum 20 with light modulated based on image data. In addition, the cleaning device 25 cleans the peripheral surface of the photosensitive drum 20 after the toner image has been transferred.

The developing device 23 supplies toner to the peripheral surface of the photosensitive drum 20 . The developing device 23 is for a two-component developer composed of toner and carrier. The toner of the developing device 23 is supplied to the peripheral surface of the photosensitive drum 20 to develop the electrostatic latent image. In addition, in the present embodiment, the toner has a characteristic of being positively charged.

Intermediate transfer belt 14 is disposed in a space provided between image forming unit 13 and toner supply unit 15 . The intermediate transfer unit 14 includes an intermediate transfer belt 141 , a drive roller 142 , a tension roller 143 , a plurality of primary transfer rollers 24 (transfer rollers), and a belt cleaning device 144 .

The intermediate transfer belt 141 is an endless belt-shaped rotating body, and is stretched over the drive roller 142 and the tension roller 143 so that the peripheral surface sides of the intermediate transfer belt 141 are in contact with the peripheral surfaces of the respective photosensitive drums 20 . . The intermediate transfer belt 141 is rotationally driven in one direction along the second direction, and bears the toner images transferred by the plurality of photosensitive drums 20 on the surface. The intermediate transfer belt 141 is a conductive soft belt having a laminated structure consisting of a base layer, an elastic layer, and a coating layer.

The drive roller 142 stretches the intermediate transfer belt 141 over the right end side of the intermediate transfer unit 14 , and drives the intermediate transfer belt 141 in rotation. The drive roller 142 is made of a metal roller. The tension roller 143 tensions the intermediate transfer belt 141 on the left end side of the intermediate transfer unit 14 . The tension roller 143 applies tension to the intermediate transfer belt 141 . A belt cleaning device 144 (see FIG. 1 ) for removing toner remaining on the peripheral surface of the intermediate transfer belt 141 is disposed near the tension roller 143 .

The primary transfer roller 24 is disposed opposite to the photosensitive drum 20 with the intermediate transfer belt 141 interposed therebetween. As a result, the primary transfer roller 24 forms a primary transfer nip between itself and the photosensitive drum 20 , and primary transfers the toner image on the photosensitive drum 20 to the intermediate transfer belt 141 . As shown in FIG. 1 , the primary transfer rollers 24 are disposed opposite to the photosensitive drums 20 of the respective colors. The primary transfer roller 24 is a roller extending in the front-rear direction, and rotates together with the intermediate transfer belt 141 .

The secondary transfer roller 145 is arranged opposite to the driving roller 142 with the intermediate transfer belt 141 interposed therebetween. The secondary transfer roller 145 is pressed against the peripheral surface of the intermediate transfer belt 141 to form a secondary transfer nip. The toner image primarily transferred onto the intermediate transfer belt 141 is secondarily transferred onto the sheet P fed by the paper feeding portion 12 at the secondary transfer portion.

The toner supply unit 15 stores toner used for image formation. In the present embodiment, the toner supply unit 15 includes a magenta toner container 15M, a cyan toner container 15C, and a yellow toner container. toner container 15Y and black toner container 15Bk. These toner containers 15M, 15C, 15Y, and 15Bk respectively store the replenishment toners of the respective colors of MCYBk, and are supplied to the respective colors of MCYBk from the toner discharge port 15H formed on the bottom surface of the containers through a toner conveying unit (not shown). The developing devices 23 of the corresponding image forming units 13M, 13C, 13Y, and 13Bk replenish the toners of the respective colors.

The fixing section 16 fixes the toner image transferred onto the sheet P. As shown in FIG.

The paper discharge section 17 is formed by denting the top of the apparatus main body 11 , and a paper discharge tray 171 that receives discharged sheets P is formed at the bottom of the recess. The sheet P subjected to the fixing process is discharged to the discharge tray 171 via the sheet conveying path 111 extending from the upper part of the fixing unit 16 .

Next, the intermediate transfer unit 14 according to the first embodiment of the present invention will be described in detail with reference to FIGS. 2A to 4 on the basis of FIG. 1 . 2A and 2B obliquely show the intermediate transfer unit 14 according to the first embodiment. 3A and 3B show enlarged oblique views of a part of the intermediate transfer unit 14 according to the first embodiment. Similarly, FIG. 4 shows an enlarged oblique view of a part of the intermediate transfer unit 14 according to the first embodiment.

The intermediate transfer unit 14 is a unit formed of a thin rectangular parallelepiped extending in the front-rear and left-right directions. As shown in FIG. 2A , the intermediate transfer unit 14 extends long in the left-right direction. The intermediate transfer unit 14 has a unit front wall 51 (side wall) and a unit rear wall 52 (side wall). The unit front wall 51 and the unit rear wall 52 are a pair of side walls arranged to extend in the left-right direction on both end sides in the front-rear direction. The unit front wall 51 and the unit rear wall 52 are frames made of a resin material. The unit front wall 51 and the unit rear wall 52 support the intermediate transfer belt 141 in a rotatable manner. Specifically, the aforementioned driving roller 142 , tension roller 143 , and the plurality of primary transfer rollers 24 are rotatably supported by the unit front wall 51 and the unit rear wall 52 . In addition, the aforementioned belt cleaning device 144 is supported on the left end sides of the unit front wall 51 and the unit rear wall 52 . When the right cover unit 10R is opened from the apparatus main body 11 , the intermediate transfer unit 14 is installed in the apparatus main body 11 in the arrow DH direction of FIGS. 1 and 2A . At this time, the intermediate transfer unit 14 is disposed adjacent to the photosensitive drums 20 above the plurality of photosensitive drums 20 .

The intermediate transfer unit 14 further includes a front plate 53, a first fixed leg 51S (leg), a second fixed leg 52S (leg), and a movable leg 60 (leg). The front plate 53 is a sheet metal member attached to the left end side of the unit front wall 51 from the front. The front plate 53 is fixed to the unit front wall 51 by a plurality of screws. The first fixed leg 51S, the second fixed leg 52S, and the movable leg 60 are legs arranged at the lower end portions of the unit front wall 51 and the unit rear wall 52 . When the intermediate transfer unit 14 is detached from the apparatus main body 11 , these leg portions come into contact with a predetermined installation surface (floor), thereby functioning to support the intermediate transfer unit 14 .

Referring to FIG. 2A and FIG. 3A , the first fixed leg portion 51S protrudes downward from the lower portion on the right end side of the unit front wall 51 . In addition, referring to FIG. 2B and FIG. 3B , the second fixed leg portion 52S protrudes downward from the lower portion of the center portion in the left-right direction of the unit rear wall 52 . Furthermore, a movable leg 60 is provided at the left end portion of the unit front wall 51 .

FIG. 5 is an exploded perspective view showing a part of the intermediate transfer unit 14 of FIG. 4 . Fig. 6 obliquely shows a state in which the movable leg 60 is detached from the intermediate transfer unit 14 of Fig. 4 . FIG. 7 obliquely shows a state where the movable leg portion 60 is attached to the intermediate transfer unit 14 of FIG. 6 . FIG. 8 shows an enlarged and oblique view of a part of the movable leg 60 in FIG. 7 . FIG. 9 shows the movable leg 60 according to the first embodiment from the front. FIG. 10 shows a cross section along the horizontal direction of the movable leg portion 60 in the A-A cross section of FIG. 9 .

Referring to FIGS. 5 and 6 , the unit front wall 51 includes a shaft portion 510 , a first engaging protrusion 511 (see FIG. 6 ), and a second engaging protrusion 512 (see FIG. 6 ). The shaft portion 510 is a cylindrical protrusion protruding forward (first direction) from the left end portion of the unit front wall 51 . The first engaging protrusion 511 and the second engaging protrusion 512 are substantially rectangular parallelepiped protrusions protruding forward from the unit front wall 51 above the shaft portion 510 . As shown in FIG. 6 , a slight gap is formed between the first engaging protrusion 511 and the second engaging protrusion 512 .

The movable leg 60 can rotate around the shaft 510 . The movable leg can change its posture between the first posture and the second posture. The first posture is a posture in which the intermediate transfer unit 14 detached from the apparatus main body 11 can be supported on the ground (installation surface). The second posture is a posture turned around the shaft portion 510 from the first posture. In the first posture, the lower end of the movable leg 60 is at the same height as the lower ends of the first fixed leg 51S and the second fixed leg 52S. On the other hand, in the second posture, the lower end of the movable leg 60 retracts upward compared to the lower ends of the first fixed leg 51S and the second fixed leg 52S.

The movable leg portion 60 is formed of a plate-shaped member that crosses the front-rear direction and is arranged to face the unit front wall 51 . The movable leg 60 is formed in a substantially fan-shaped shape. The movable leg portion 60 includes a main body portion 601, a hole portion 602, an engaging hole 603, an outer peripheral portion 604, a rib 605, a first protrusion 606, and a second protrusion 607 (see FIG. 7 ).

The main body portion 601 is a main body portion of the movable leg portion 60 formed in a substantially fan-shaped shape. The main body portion 601 is rotatable around the shaft portion 510 . As shown in FIG. 7 , the three corners of the main body 601 are arc-shaped. The hole portion 602 is a substantially circular hole formed through the main body portion 601 of the movable leg portion 60 in the front-rear direction on the upper end side of the main body portion 601. The aforementioned shaft portion 510 is inserted through the hole portion 602 .

The engaging hole 603 is a rectangular hole formed directly below the hole portion 602 to penetrate the main body portion 601 of the movable leg portion 60 in the front-rear direction. The engaging hole 603 has a smaller opening than the hole portion 602 . Referring to FIG. 10 , the engaging hole 603 has a tapered shape (tapered portion 603T) widening toward the unit front wall 51 (rear).

The outer peripheral portion 604 is a part of the main body portion 601 and is formed at the lower end portion of the movable leg portion 60 . As shown in FIG. 7 , the outer peripheral portion 604 has an arc shape having a predetermined width in the radial direction centered on the hole portion 602 . In addition, the outer peripheral portion 604 is arranged to have a step with respect to the upper end portion of the main body portion 601 , and is arranged in front of the upper end portion of the main body portion 601 . When the intermediate transfer unit 14 is detached from the apparatus main body 11 , the outer peripheral edge 604R of the outer peripheral portion 604 can be in contact with the ground.

The rib 605 is a protrusion arranged on the main body portion 601 so as to be in contact with the outer peripheral portion 604 . A plurality of ribs 605 are arranged at intervals in the circumferential direction of the arc shape of the outer peripheral portion 604 . Due to the plurality of ribs 605, the rigidity of the movable leg 60 is set high. As a result, even in the case where the intermediate transfer unit 14 is supported by the movable leg 60 , damage to the movable leg 60 can be prevented.

The first protrusion 606 and the second protrusion 607 protrude from the outer peripheral edge 604R at intervals in the circumferential direction so as to sandwich the lowermost end portion of the outer peripheral edge 604R of the outer peripheral portion 604 in the first posture shown in FIG. 7 . Set of a pair of protrusions.

Furthermore, the intermediate transfer unit 14 includes a bias spring 61 (see FIGS. 5 and 6 ). The bias spring 61 is a torsion spring that biases the movable leg 60 around the shaft portion 510 so that the movable leg 60 assumes the first posture. The biasing spring 61 is disposed between the movable leg 60 and the unit front wall 51 , and is fitted on the shaft portion 510 . The bias spring 61 has a first spring end 611 and a second spring end 612 . The first spring end 611 is one end of the bias spring 61 made of a linear member. The first spring end 611 is engaged between the first engaging protrusion 511 and the second engaging protrusion 512 of the unit front wall 51 . The second spring end 612 is the other end of the biasing spring 61 . The second spring end 612 is engaged in the engaging hole 603 of the movable leg 60 .

Referring to FIG. 8 , the hole portion 602 includes an upper inner peripheral surface 602A and a lower inner peripheral surface 602B. The upper inner peripheral surface 602A is an upper end portion of the inner peripheral surface of the hole portion 602 . As shown in FIG. 7 , when the movable leg portion 60 is in the first posture, the upper inner peripheral surface 602 faces the upper end side of the shaft portion 510 . Likewise, the lower inner peripheral surface 602B is the lower end portion of the inner peripheral surface of the hole portion 602 . In addition, the lower inner peripheral surface 602B is formed by slightly extending the lower end side of the substantially circular hole 602 downward. Therefore, when viewed from the center (axis center) of the shaft portion 510 , the lower inner peripheral surface 602B is arranged farther than the upper inner peripheral surface 602A. As shown in FIGS. 7 and 8 , when the movable leg portion 60 is in the first posture, the lower inner peripheral surface 602B faces the lower end side of the shaft portion 510 .

Furthermore, the intermediate transfer unit 14 includes a high sliding member 602S (high friction member) (see FIG. 8 ). The high sliding member 602S is a rubber member adhered to the lower inner peripheral surface 602B. In a state where the movable leg 60 is in contact with the ground in the first posture, the high slide member 602S functions as a restriction mechanism that restricts the rotation of the movable leg 60 around the shaft portion 510 . In addition, in other embodiments, the high sliding member 602S may be fixed to the lower end portion of the peripheral surface of the shaft portion 510 .

As shown in FIG. 6 , the first spring end 611 of the bias spring 61 is engaged between the first engaging protrusion 511 and the second engaging protrusion 512 , and the bias spring 61 is fitted onto the shaft portion 510 . Furthermore, the second spring end portion 612 is inserted into the engaging hole 603 of the movable leg portion 60, and the hole portion 602 is externally fitted on the shaft portion 510 (see FIG. 7 ). At this time, since the engaging hole 603 has the tapered portion 603T, the second spring end portion 612 can be easily fitted into the engaging hole 603 . The shaft portion 510 behind the through hole portion 602 is inserted into a plate hole portion 531 (see FIG. 5 ) opened in the front plate 53. As shown in FIG. In this state, the movable leg portion 60 is rotatably supported about the shaft portion 510 while the front plate 53 is fastened to the unit front wall 51 .

When the intermediate transfer unit 14 is detached from the apparatus main body 11, the intermediate transfer unit 14 can be placed directly on the floor (prescribed installation surface). As a result, the maintainability of the detached intermediate transfer unit 14 or the device main body 11 having a hollow interior can be improved. The intermediate transfer unit 14 is provided with at least three legs (the first fixed leg 51S, the second fixed leg 52S, and the movable leg 60 ). Therefore, when directly placed, intermediate transfer belt 141 does not come into contact with the ground, and damage to intermediate transfer belt 141 can be suppressed.

As mentioned above, the biasing spring 61 biases the movable leg 60 so that the movable leg 60 assumes the first posture (refer to FIG. 2A, FIG. 4 and FIG. 7 ). Therefore, when the intermediate transfer unit 14 is detached from the apparatus main body 11, the movable leg portion 60 quickly assumes the first posture. Therefore, direct placement of the intermediate transfer unit 14 is easily achieved.

In addition, as described above, the intermediate transfer unit 14 is arranged adjacent to the plurality of photosensitive drums 20 . Inside the apparatus main body 11 , the intermediate transfer belt 141 of the intermediate transfer unit 14 must abut against the photosensitive drum 20 . On the other hand, in order to protect the intermediate transfer belt 141 when the intermediate transfer unit 14 is detached from the apparatus main body 11 , it is necessary to protrude the movable leg portion 60 below the intermediate transfer belt 141 . In a state where the movable leg 60 continues to protrude downward compared to the intermediate transfer belt 141 , if the intermediate transfer unit 14 is installed in the apparatus main body 11 , the photosensitive drum 20 or others with the movable leg 60 will be interfered with. The condition of the unit. At this time, the installation of the intermediate transfer unit 14 may be hindered or the units may be damaged each other.

In this embodiment, when the detached intermediate transfer unit 14 is reinstalled in the apparatus main body 11 , the movable leg portion 60 can rotate around the shaft portion 510 . Therefore, even in the case where the intermediate transfer unit 14 is installed while being close to the photosensitive drum 20 or other units, interference (hard contact) of the movable leg portion 60 with these units can be prevented. In other words, when the movable leg 60 comes into contact with these units and is pressed, since the posture of the movable leg 60 is quickly changed to the second posture, mutual damage can be prevented.

In particular, when the movable leg 60 rotates from the first posture around the shaft portion 510 to the front end side in the second direction (arrow D2 direction in FIG. 4 ) or the rear end side in the second direction (arrow D1 direction in FIG. 4 ), The pose changes to the second pose. That is, the movable leg portion 60 can rotate in any direction around the shaft portion 510 . Therefore, when the intermediate transfer unit 14 is attached or detached, it is possible to prevent the movable leg portion 60 from interfering with other units.

When the intermediate transfer unit 14 is attached to the apparatus main body 11, if the outer peripheral left end portion 604A (refer to FIG. Turn in direction of arrow D1. Thereafter, when the intermediate transfer unit 14 is mounted inside the apparatus main body 11 , since the movable leg 60 can be arranged in a predetermined space, the posture of the movable leg 60 is changed to the first posture again. On the other hand, when the intermediate transfer unit 14 is detached from the apparatus main body 11, if the outer peripheral right end portion 604B (refer to FIG. The movable leg part 60 rotates in the direction of arrow D2. Thereafter, when the intermediate transfer unit 14 is detached from the apparatus main body 11 , the posture of the movable leg 60 is changed to the first posture again. As a result, intermediate transfer unit 14 can be placed on the ground.

When the intermediate transfer unit 14 is placed on the ground, since the outer peripheral portion 604 of the movable leg 60 has an arc shape, even if the posture of the movable leg 60 fluctuates, the intermediate transfer can be stably maintained. The distance between the printing belt 141 and the ground. In addition, in this embodiment, the outer peripheral edge 604R is equipped with the 1st protrusion 606 and the 2nd protrusion 607 (refer FIG. 7). Therefore, even when a force in the horizontal direction is applied to the intermediate transfer unit 14 placed on the ground, the excess of the movable leg portion 60 is restricted by bringing the first protrusion 606 and the second protrusion 607 into contact with the ground. turn. Therefore, the fall of the intermediate transfer unit 14 can be suppressed, and the damage of the intermediate transfer belt 141 can be suppressed.

In addition, in the present embodiment, the high sliding member 602S functions as a restriction mechanism. That is, when the intermediate transfer unit 14 is placed on the ground outside the apparatus main body, the lower end of the shaft portion 510 strongly abuts against the high sliding member 602S due to the dead weight of the intermediate transfer unit 14 . Therefore, the rotation of the movable leg portion 60 is restricted by increasing the friction between the shaft portion 510 and the inner peripheral surface of the hole portion 602 . Also, when the intermediate transfer unit 14 is lifted from the ground, the upper end side of the shaft portion 510 comes into contact with the upper inner peripheral surface 602A of the hole portion 602 due to the dead weight of the movable leg portion 60 (see FIG. 8 ). At this time, a slight gap is formed between the lower end side of the shaft portion 510 and the high sliding member 602S. Therefore, the movable leg 60 can be easily turned inside the device main body 11 .

Next, the movable leg portion 60 according to the second embodiment of the present invention will be described. FIG. 11 shows the periphery of the movable leg portion 60 of the intermediate transfer unit 14 according to the second embodiment from the front. FIG. 12 shows an enlarged front view of a part of the movable leg 60 in FIG. 11 . In addition, in the second embodiment, compared with the previous first embodiment, the difference is that the first gear teeth 510G and the second gear teeth 610G are provided instead of the high sliding member 602S of the movable leg 60, so The differences will be mainly described, and the description of the common points will be omitted.

Referring to FIG. 11 and FIG. 12 , the shaft portion 510 includes first gear teeth 510G. In addition, the movable leg portion 60 includes second teeth 601G. The first teeth 510G are a plurality of teeth arranged adjacent to each other in the circumferential direction on the lower end side of the shaft portion 510 . On the other hand, the second teeth 601G are disposed on the lower inner peripheral surface 602B (see FIG. 8 ) of the hole portion 602 and are a plurality of teeth capable of engaging with the first teeth 510G. In the present embodiment, the first teeth 510G and the second teeth 601G function as restricting means.

That is, when the intermediate transfer unit 14 is placed on the ground outside the apparatus main body 11 , due to the dead weight of the intermediate transfer unit 14 , the first gear teeth 510G of the shaft portion 510 and the second gear teeth of the movable leg portion 60 601G bite. In this state, when a force in the horizontal direction is applied to the intermediate transfer unit 14 , the rotation of the movable leg portion 60 is restricted by the meshing of the first teeth 510G and the second teeth 601G. In addition, when the intermediate unit belt 14 is lifted from the ground in this state, the upper end side of the shaft portion 510 comes into contact with the upper inner peripheral surface 602A of the hole portion 602 due to the own weight of the movable leg portion 60 (see FIG. 12 ). . At this time, a slight gap is formed between the first tooth 510G and the second tooth 601G of the shaft portion 510 . Therefore, the movable leg 60 can easily rotate inside the device main body 11 without the first teeth 510G engaging with the second teeth 601G.

Next, the movable leg portion 60 according to the third embodiment of the present invention will be described. FIG. 13 shows obliquely the periphery of the movable leg portion 60 of the intermediate transfer unit 14 according to the third embodiment of the present invention. FIG. 14 shows a slanted view of the movable leg portion 60 and the unit detection unit 70 (also referred to as a detection unit) of the intermediate transfer unit 14 according to the third embodiment. FIG. 15 shows enlarged and obliquely the movable leg portion 60 and the unit detection portion 70 of FIG. 14 . In addition, in the third embodiment, compared with the previous first embodiment, the difference is that the movable leg 60 has a cleaning part 604P (also referred to as a cleaning member), and the intermediate transfer unit 14 has a unit detection part. 70 and the drive mechanism G, so the description will focus on the differences, and the description of the common points will be omitted.

In this embodiment, the movable leg part 60 is equipped with the cleaning part 604P. The cleaning portion 604P is a sponge member provided on the front side surface of the outer peripheral portion 604 . In addition, in other embodiments, the cleaning part 604P may be a brush member, and may also be a member having other cleaning functions.

The unit detection unit 70 is a PI sensor (optical sensor) provided in the main body 11 of the image forming apparatus 10 . The unit detection unit 70 can detect the movable leg 60 in the device main body 11 . The unit detection unit 70 includes a unit main body 700 , a light emitting unit 701 , a light receiving unit 702 , and a joint unit 703 . The detection light emitted from the light emitting unit 701 is received by the light receiving unit 702 . At this time, as shown in FIG. 15 , if the outer peripheral portion 604 of the movable leg portion 60 is disposed between the light emitting portion 701 and the light receiving portion 702 , the detection light is blocked. As a result, a control unit (not shown) disposed in the apparatus main body 11 detects the state of the intermediate transfer unit 14 in the apparatus main body 11 . The connector unit 703 is electrically connected to the control unit via an unillustrated electric board inside the device main body 11.

The drive mechanism G is provided inside the device main body 11 . The drive mechanism G includes an electric motor (not shown), a gear set connected to the electric motor, and a rotatable cam connected to the gear set. The drive mechanism G moves the primary transfer roller 24 of the intermediate transfer unit 14 up and down inside the apparatus main body 11 . Specifically, the drive mechanism G changes the state of the intermediate transfer unit 14 between the first state and the second state. When the intermediate transfer unit 14 is in the first state, the primary transfer rollers 24 of the respective colors are in contact with the photosensitive drums 20 via the intermediate transfer belt 141 . On the other hand, when the intermediate transfer unit 14 is in the second state, the primary transfer rollers 24 of the respective colors are separated upward from the photosensitive drums 20 . Further, the movable leg portion 60 slides to the left and right between the first position and the second position according to the state change of the intermediate transfer unit 14 by a sliding mechanism not shown. The sliding movement of the movable leg portion 60 can be detected by the aforementioned unit detection unit 70 . Therefore, the unit detection section 70 can detect a change in the state of the intermediate transfer unit 14 accompanying a change in the position of the movable leg section 60 .

According to this configuration, the not-illustrated control unit included in the apparatus main body 11 can execute the image forming operation in the first state of the intermediate transfer unit 14 . On the other hand, when the intermediate transfer unit 14 is taken out from the apparatus main body 11 , the drive mechanism G is controlled by the control unit in advance to change the intermediate transfer unit 14 from the first state to the second state. At this time, the transition of the intermediate transfer unit 14 to the second state (state change) is detected by the unit detection unit 70 detecting the sliding movement of the movable leg portion 60 . Therefore, the intermediate transfer belt 14 can be detached while the primary transfer roller 24 moves upward and strong sliding friction between the intermediate transfer belt 14 and the photosensitive drum 20 is suppressed.

In addition, in this embodiment, like the previous first embodiment, when the intermediate transfer unit 14 is attached to the apparatus main body 11, the movable leg portion 60 is in the first posture. And, when the intermediate transfer unit 14 is inserted into the apparatus main body 11 , the cleaning portion 604P of the movable leg portion 60 comes into contact with the light emitting portion 701 of the unit detection portion 70 and cleans the light emitting portion 701 . In particular, in this embodiment, a belt cleaning device 144 is provided near the movable leg 60 as in the first embodiment. Therefore, if a little toner scattered from the cleaning device 144 adheres to the light emitting portion 701, the irradiation of the detection light becomes unstable. In the present embodiment, since the light emitting unit 701 is cleaned as the intermediate transfer unit 14 is attached and detached, the detection light is stably emitted, and the detection accuracy of the unit detection unit 70 can be stably maintained. In addition, in other embodiments, the cleaning unit 604P may also clean the light receiving unit 702 . In addition, in the present embodiment, since the unit detection unit 70 is provided on the apparatus main body 11 , the unit detection unit 70 is cleaned every time the intermediate transfer unit 14 is detached from the apparatus main body 11 . In addition, the cost of the intermediate transfer unit 14 can be appropriately reduced.

Next, the movable leg portion 60 according to the fourth embodiment of the present invention will be described. FIG. 16 shows obliquely the periphery of the movable leg portion 60 of the intermediate transfer unit 14 according to the fourth embodiment. FIG. 17 obliquely shows a state where the movable leg portion 60 is detached from the intermediate transfer unit 14 of FIG. 16 . In addition, since the fourth embodiment differs from the previous first embodiment in that the movable leg portion 60 includes a belt support portion 60L, the description will focus on the difference and the description of the common points will be omitted.

In this embodiment, the movable leg part 60 is arrange|positioned at the center part of the unit front wall 51 in the left-right direction. On the other hand, a pair of leg portions (not shown) are arranged at both ends in the left-right direction of the unit rear wall 52 . The unit front wall 51 includes a central plate portion 55 . The central plate portion 55 is a plate-shaped portion provided on the lower end of the unit front wall 51 facing forward. The central plate portion 55 includes a shaft portion 550 . When the hole 602 of the movable leg 60 is inserted into the shaft 550 , the movable leg 60 can be turned. In addition, the central plate portion 55 is provided with a first engaging protrusion 551 and a second engaging protrusion 552 (see FIG. 17 ), similarly to the foregoing first embodiment. The first spring end 611 of the bias spring 61 is engaged between the first engaging protrusion 551 and the second engaging protrusion 552 . On the other hand, the second spring end 612 of the biasing spring 61 is snapped to the movable leg 60 .

In this embodiment, the movable leg portion 60 includes a belt support portion 60L. The belt support portion 60L is a rod-shaped protruding piece protruding rearward from the rear side surface of the movable leg portion 60 . As shown in FIG. 16 , when the movable leg portion 60 is in the first posture, the belt support portion 60L extends below the central plate portion 55 to extend in the front-rear direction. The belt support portion 60L can support the lower surface portion of the intermediate transfer belt 141 from below. According to this configuration, even when the intermediate transfer unit 14 is placed directly on the floor after detaching from the apparatus main body 11 , damage to the intermediate transfer belt 141 hanging downward can be prevented.

The intermediate transfer unit 14 and the image forming apparatus 10 including the intermediate transfer unit 14 according to the respective embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. The present invention can take, for example, the following modified embodiments.

(1) In the above-mentioned first embodiment, the legs of the intermediate transfer unit 14 are made up of the three legs of the first fixed leg 51S, the second fixed leg 52S, and the movable leg 60 . description, but the present invention is not limited thereto. The intermediate transfer unit 14 only needs to have at least three or more legs. In this case, at least one leg portion may be provided on the unit front wall 51 and the unit rear wall 52 .

(2) In the above-mentioned first embodiment, an embodiment in which only the movable leg portion 60 is rotatable among the three leg portions has been described, but the present invention is not limited thereto. The first fixed leg portion 51S and the second fixed leg portion 52S may be configured to be rotatable in the same manner as the movable leg portion 60 .

Claims (11)

1. An image forming device comprising: The device main body includes a plurality of photosensitive drums that rotate around an axis extending in a first direction and are adjacently arranged at predetermined intervals in a second direction intersecting the first direction; and An intermediate transfer unit is installed in the second direction adjacent to the plurality of photosensitive drums with respect to the apparatus main body, the intermediate transfer unit includes an intermediate transfer belt, and the intermediate transfer belt rotationally driven in the second direction and bear on a surface toner images transferred from the plurality of photosensitive drums, wherein, The intermediate transfer unit also has: A plurality of transfer rollers are arranged opposite to the photosensitive drum through the intermediate transfer belt; a pair of side walls configured to extend in the second direction on both end sides in the first direction, and to rotatably support the intermediate transfer belt; and A plurality of leg portions abuts on a predetermined installation surface when the intermediate transfer unit is detached from the apparatus main body, at least three of the leg portions are arranged on lower end portions of the pair of side walls, At least one of the pair of side walls has a shaft protruding in the first direction, At least one of the plurality of legs is a movable leg that is rotatable around the shaft and capable of supporting a first side of the intermediate transfer unit detached from the device main body. a position change is possible between a position and a second position rotated from the first position around the shaft portion, When the intermediate transfer unit is mounted on the apparatus main body, the movable leg is in the first posture, The image forming apparatus further has: a detection section capable of detecting the movable leg within the device main body; and a drive mechanism for causing the intermediate transfer unit to be in a first state where the transfer roller is in contact with the photosensitive drum and a second state where the transfer roller is separated from the photosensitive drum in the device main body between state changes, The position of the movable leg is changed between a first position and a second position accompanying the state change of the intermediate transfer unit between the first state and the second state, The detection section detects the change in the state of the intermediate transfer unit accompanying the change in the position of the movable leg, The movable leg portion further includes a cleaning member that is capable of cleaning the detection portion in contact with the detection portion when the intermediate transfer unit is attached to the apparatus main body. 2. The image forming apparatus according to claim 1, The posture of the movable leg is changed to the second posture by turning from the first posture to the front end side in the second direction or the rear end side in the second direction around the shaft portion. 3. The image forming apparatus according to claim 1, The image forming apparatus further includes: A biasing member for biasing the movable leg around the shaft so that the movable leg assumes the first posture. 4. The image forming apparatus according to claim 3, The movable leg has a plate-like member intersecting the first direction and facing the one side wall, The biasing member includes a torsion spring disposed between the movable leg and the one side wall and fitted onto the shaft, The movable leg has an engaging hole formed through the movable leg along the first direction, one end of the biasing member is engaged to the one side wall, and the other end of the biasing member is engaged to the engaging hole, The engaging hole has a tapered shape expanding toward the front end of the one side wall. 5. The image forming apparatus according to claim 1, The movable leg has: a hole portion inserted into the shaft portion; and a main body portion capable of rotating about the shaft portion, The main body includes an outer peripheral portion having an arcuate shape centering on the hole, and when the intermediate transfer unit is detached from the apparatus main body, the outer peripheral portion comes into contact with the installation surface. 6. The image forming apparatus according to claim 5, The main body portion includes a pair of protrusions spaced apart from the arc-shaped circumferential direction so as to sandwich the lowermost end portion of the outer peripheral portion in the first posture. The outer peripheral part protrudes. 7. The image forming apparatus according to claim 5, In the movable leg arranged in the first posture, the hole portion has an upper inner peripheral surface facing the upper end side of the shaft portion and a lower side facing the lower end side of the shaft portion. inner peripheral surface, The intermediate transfer unit further includes a restriction mechanism for restricting the movable leg to rotate around the axis in a state where the movable leg is in contact with the installation surface in the first posture. Department rotation. 8. The image forming apparatus according to claim 7, The restricting mechanism includes a high-friction member disposed on the lower end side of the shaft portion or on the lower inner peripheral surface. 9. The image forming apparatus according to claim 7, The limiting agencies include: a first gear tooth disposed on a lower end side of the shaft portion; and The second teeth are arranged on the lower inner peripheral surface and can be engaged with the first teeth. 10. The image forming apparatus according to claim 1, The image forming apparatus further has: A belt support portion extending from the movable leg portion in the first direction, capable of supporting the intermediate transfer belt from below in the first posture. 11. The image forming apparatus according to any one of claims 1 to 10, The detection unit is provided on the device main body side.